How foamy is spacetime

first_imgThe HST’s high-resolution image of the Airy ring surrounding the quasar ruled out the random-walk model, but lacked sufficient resolution to test the holographic model. “By using this image, they’ve shown that the archives of all the great telescopes — both the interferometers as well as single telescopes like the HST — can be used to make very fundamental measurements about the structure of our universe,” said Eric Perlman, physicist at the University of Maryland who initially observed the quasar.Telescopes currently being built could capture even higher resolution images for future studies.“In the next few years, interferometers – such as the Very Large Telescope Interferometer in Chile or the Keck Interferometer in Hawaii – could test the holographic model by observing more distant quasars with their large apertures and long baselines,” said Christiansen. Cosmological ImplicationsHowever, the team didn’t depend on further observations to deduce another cosmological implication in addition to measuring quantum foam. Observationally ruling out the random-walk model, coupled with restrictions from computational physics, has repercussions on the matter of spacetime. Because ordinary matter only contains an amount of information dense enough to map out spacetime at a level consistent with the random-walk model, the physicists suggest that “there must be other kinds of matter or energy with which the Universe can map out its spacetime geometry (to a finer spatial accuracy than is possible with the use of conventional matter).“This line of reasoning strongly hints at the existence of dark matter and dark energy, independent of the evidence from recent cosmological observations.”Although the universe may not be quite as foamy as some scientists previously suspected, the team has put constraints on the foaminess of spacetime, and supplied another parameter with which to probe unconventional matter and energy. The group has also holds high hopes for learning more about spacetime structure in the near future.“I think there is a close relation between quantum foam and dark matter and dark energy,” said Ng. “More work on holographic-foam-inspired cosmology is now in progress. Stay tuned.”Citation: Christiansen, W.A., Ng, Y. Jack, and van Dam, H. Probing Spacetime Foam with Extragalactic Sources. Physical Review Letters. 96, 051301 (2006).By Lisa Zyga, Copyright 2006 PhysOrg.com Maybe not as foamy as some scientists thought, as a fresh look at a quasar first observed in 1998 by the Hubble Space Telescope (HST) shows. Physicists observed a diffraction pattern called an Airy ring around the image of a distant quasar-like object. This ring persuades physicists that the light from this distant object has traveled through a relatively calm – rather than extremely frothy – spacetime. This image is a linear combination of two images first observed by Perlman et al. for research studying the relationship between this quasar and its galaxy. In the image, the ring surrounds the nucleus of the galaxy, making it look iris-like rather than just pseudo-point-like. Image courtesy of Eric Perlman. NASA telescopes set limits on space-time quantum ‘foam’ Citation: How foamy is spacetime? (2006, February 10) retrieved 18 August 2019 from https://phys.org/news/2006-02-foamy-spacetime.htmlcenter_img The idea that space is composed of ever-changing arrangements of bubbles, called spacetime foam, dates back to the 1960s. On a small (Planck) scale, foamy bubbles result from the uncertainty principle, which allows virtual particles to spontaneously pop into and out of existence. Although quantum foam violates the law of conservation of energy on ultra-short timescales, nanoscale devices have measured the effects of these tiny virtual particles on the vacuum in other contexts. Further, many physicists believe that some model of quantum foam must exist in any theory of quantum gravity, which unites quantum mechanics and general relativity. “The detection of spacetime foam will give us a glimpse of the ultimate structure of spacetime,” said Y. Jack Ng, member of the team that observed the ring. “The observational results may also point physicists to the correct theory of quantum gravity.”Ng and his colleagues, W.A. Christiansen and H. van Dam from the University of North Carolina, have narrowed down the possible models of quantum foam into the least foamy variations. The team compared two spacetime foam models based on quantum fluctuations in spacetime geometry. The first model is consistent with the holographic principle, which stipulates that the maximum amount of information that any region of space can store is proportional to its surface area instead of its volume, like a hologram. The second model, called the random-walk model, stipulates that successive fluctuations are random, totally uncorrelated. The holographic model enables a less turbulent spacetime compared with the random-walk model, which involves greater fluctuations.The team chose to analyze the quasar-like object PKS1413 + 135 to search for an Airy ring because the presence of a ring limits the amount of light scattering that could be caused by spacetime foam. The quasar is 1.2 gigaparsecs – or about 4 billion light years – away from the Milky Way, allowing the physicists to accumulate the effects of the fluctuations over a distance, necessary for amplifying the tiny effects of the foam.“Searching for spacetime foam effects is limited to point-like objects like PKS1413 +135 because objects greater than point-like size – such as galaxies – can contain an intrinsic structure that masks the effects of quantum foam,” said Christiansen. Explore further This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

Darwins Tree of Life May Be More Like a Thicket

first_img Citation: Darwin’s Tree of Life May Be More Like a Thicket (2009, January 27) retrieved 18 August 2019 from https://phys.org/news/2009-01-darwin-tree-life-thicket.html (PhysOrg.com) — In On The Origin of Species, Darwin used the image of a tree of life to illustrate how species evolve, one from another. Even today, branches sprouting from lower branches (representing ancestors) is how many people view the evolution of species. Explore further A page from Darwin’s notebook showing the tree of life. Discovery of jumping gene cluster tangles tree of life However, for some time, evolutionary biologists have known that the picture is not quite so clear. A recent feature article in New Scientist investigates the current views of biologists – that organisms may pass traits not just to their offspring, but to other living organisms – and suggests that uprooting the tree of life may be the start of a revolutionary change in biology.The possibility that evolution isn’t as clear as the tree of life is not a brand new idea to biologists, but it has slowly risen from various studies. In the 1950s and following decades, the discovery of DNA, RNA, and protein sequences revealed that species once thought to be near each other on the tree are in fact quite different, molecularly speaking. In the early ’90s, scientists had hoped that gene sequencing would help them piece together the tree of life, but instead it showed conflicting results. For instance, some species that are closely related based on their DNA are not closely related at all based on their RNA.In order to make sense of the conflicts, biologists had to reconstruct Darwin’s tree, which assumed that organisms primarily pass their traits down to their offspring. Besides this “vertical” gene transfer, organisms may also share traits through “horizontal” gene transfer with other species, or even by reproducing with other species to produce genetic hybrids. Horizontal transfer and hybridization would result in a web of life, with species sharing some traits but not others, as the molecular evidence shows. Perhaps, the tree of life is just a way for humans to classify nature, as biologist W. Ford Doolittle has suggested.Today, biologists disagree on whether horizontal gene transfer plays the prominent role in evolution, or if it just adds noise and makes it difficult to pinpoint the complex branching of the tree of life. Some scientists think that horizontal gene transfer may accurately explain the evolution of the simple organisms such as bacteria, archaea and prokaryotes such as amoeba, but that complex animals evolve vertically. But considering that these simple organisms make up 90% of all species, and have been around for 3.8 billion years whereas multi-cellular organisms appeared just 630 million years ago, a linear tree of complex creatures would be more like a small offshoot of the overall web. But more recently, evidence suggests that complex organisms also have an evolutionary history of horizontal gene transfer and hybridization. It seems that viruses are constantly cutting and pasting DNA from one genome to another; in humans, up to half of our DNA may have been imported horizontally by viruses. In addition, hybridization occurs more commonly than previously thought. Evidence even shows that early Homo sapiens may have hybridized with some extinct related species, such as Homo erectus and the Neanderthals. While this interrelatedness makes evolution more complex than originally thought, vertical processes still explain how multi-cellular organisms are related to each other pretty well – so the tree is still useful, but just for parts, not the whole. More significantly, understanding the complexity of evolution’s branches may reveal that biology overall is more complex than it seems. As New Scientist points out, the field of biology is looking remarkably similar to that of physics around 1900 – just before groundbreaking discoveries in relativity and quantum mechanics revolutionized the field and the way we view the physical world.via: New Scientist This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

Airplane contrails worse than CO2 emissions for global warming study

first_img Explore further Photo: Ann the Doc Probing Question: Does commercial jet traffic affect climate? Airplane contrails are the white clouds that we see in the sky spreading behind jets. These cirrus clouds are created when the hot, moist air released from the plane freezes in the colder and drier air. These clouds then trap the long-wave radiation from Earth and create a warming of the atmosphere.In their study, Burkhardt and Karchar utilized satellite imagery of these spreading contrails to create a computer model which estimates how the contrails affect the Earth’s temperature.They have discovered that aviation contrails play a huge role in the impact on the climate and an even greater impact than that created by the CO2 emissions produced. While the CO2 emissions from airplanes account for around three percent of the annual CO2 emissions from all fossil fuels and change the radiation by 28 milliwatts per square meter, the aviation contrails are responsible for a change of around 31 milliwatts per square meter.The only difference is that CO2 has a longer life than that of the contrails, and can still continue to cause warming even hundreds of years down the road.The researchers believe that while continuing to reduce CO2 emissions in aviation, more work needs to be done to reduce contrails as well. This reduction of contrails could present an immediate effect on global warming. Solutions for this could include such things as creating flight plans at lower altitudes and the development of new airplane engines which would either reduce the water vapor released or immediately condense the water into ice that would drop to the ground below. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. (PhysOrg.com) — In a recent study published in Nature Climate Change, Dr. Ulrike Burkhardt and Dr. Bernd Karcher from the Institute for Atmospheric Physics at the German Aerospace Centre show that the contrails created by airplanes are contributing more to global warming that all the CO2 that has been caused by the entire 108 years of airplane flight. © 2010 PhysOrg.com Citation: Airplane contrails worse than CO2 emissions for global warming: study (2011, March 31) retrieved 18 August 2019 from https://phys.org/news/2011-03-airplane-contrails-worse-co2-emissions.html More information: Global radiative forcing from contrail cirrus, Nature Climate Change 1, 54–58 (2011) doi:10.1038/nclimate1068last_img read more

Researchers report celltocell movement of mitochondria through a graft junction of two

first_imgMitochondria. Credit: Wikipedia commons Human beings have been grafting plants for centuries, cutting a branch from one plant and pressing it against an exposed part of another has resulted in fruit trees that bear more than one type of fruit, for example. But, what has not been clear is what else happens during grafting—to the human eye it appears a grafted branch produces the type of fruit it originally would have, but not much else. But genetic research over the past decade has shown that chloroplasts can be exchanged between cells on either side of a graft, and in some cases an entire cell nucleus can be exchanged as well. In this new effort, the researchers have found that cells can exchange mitochondria also which means that plants mix their DNA together when grafting takes place.To find out more about what happens during grafting the researchers grafted one species of tobacco plant onto another, one of which had a mutation that prevented male flowers from growing in a normal way. Next, they sliced off pieces of the plant from the side of the graft that had come from a male sterile plant and planted it resulting in new plants growing individually from the ground. As those plants grew, the researchers found that some of them developed normal male flowers, which showed that mitochondrial transfer had occurred between the two species. When the team looked at the mitochondrial genomes of the plants, they found recombination of the two and were also able to identify the gene that was likely responsible for the male sterility.This new evidence blurs the line between genetically modified plants, or crops that come about due to man-made processes and those that occur naturally, because natural grafting sometimes occurs when two plants grow close to one another. Those who insist that GMOs are harmless will now have another argument to back them up because it now appears that plants have been swapping DNA naturally all along. (Phys.org)—A team of researchers with Rutgers University has found an example via experimentation, of cell-to-cell movement of mitochondria through a graft junction of two tobacco species. In their paper published in Proceedings of the National Academy of Sciences, the team describes their experiments with grafting tobacco plants and what they learned about cells swapping mitochondria during the aftermath. Journal information: Proceedings of the National Academy of Sciences Can trees really change sex? Citation: Researchers report cell-to-cell movement of mitochondria through a graft junction of two plant species (2016, March 8) retrieved 18 August 2019 from https://phys.org/news/2016-03-cell-to-cell-movement-mitochondria-graft-junction.htmlcenter_img This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. © 2016 Phys.org More information: Csanad Gurdon et al. Cell-to-cell movement of mitochondria in plants, Proceedings of the National Academy of Sciences (2016). DOI: 10.1073/pnas.1518644113AbstractWe report cell-to-cell movement of mitochondria through a graft junction. Mitochondrial movement was discovered in an experiment designed to select for chloroplast transfer from Nicotiana sylvestris into Nicotiana tabacum cells. The alloplasmic N. tabacum line we used carries Nicotiana undulata cytoplasmic genomes, and its flowers are male sterile due to the foreign mitochondrial genome. Thus, rare mitochondrial DNA transfer from N. sylvestris to N. tabacum could be recognized by restoration of fertile flower anatomy. Analyses of the mitochondrial genomes revealed extensive recombination, tentatively linking male sterility to orf293, a mitochondrial gene causing homeotic conversion of anthers into petals. Demonstrating cell-to-cell movement of mitochondria reconstructs the evolutionary process of horizontal mitochondrial DNA transfer and enables modification of the mitochondrial genome by DNA transmitted from a sexually incompatible species. Conversion of anthers into petals is a visual marker that can be useful for mitochondrial transformation. Explore furtherlast_img read more

Gravitational wave detectors to search for dark matter

first_img © 2018 Phys.org Gravitational wave detectors might be able to detect much more than gravitational waves. According to a new study, they could also potentially detect dark matter, if dark matter is composed of a particular kind of particle called a “dark photon.” In the future, LIGO (Laser Interferometer Gravitational Wave Observatory) scientists plan to implement a search for dark photons, which will include certain previously unexplored regions of the dark photon parameter space. Journal information: Physical Review Letters Explore further More information: Aaron Pierce, Keith Riles, and Yue Zhao. “Searching for Dark Photon Dark Matter with Gravitational Wave Detectors.” Physical Review Letters. DOI: 10.1103/PhysRevLett.121.061102Also at arXiv:1801.10161 [hep-ph] Gravitational wave detectors could shed light on dark mattercenter_img Sky with stars. Credit: Felix Mittermeier, Pexels.com This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. A team of physicists, Aaron Pierce, Keith Riles, and Yue Zhao from the University of Michigan, have reported their proposal for using gravitational wave detectors to search for dark matter in a recent paper published in Physical Review Letters.”This proposal nicely bridges the newly born field of gravitational wave astronomy with that of particle physics,” Zhao told Phys.org. “Without any modifications, a gravitational wave detector can be used as a very sensitive direct dark matter detector, with the potential for a five-sigma discovery of dark matter.”As the physicists explain in their paper, if dark photons have a very light mass, then they can be considered to behave like an oscillating background field, with the oscillation frequency determined by their mass. Gravitational wave detectors could potentially detect these oscillations because the oscillations may affect test objects placed in the gravitational wave detectors. For example, if two test objects located at different positions in the detector experience different displacements, this difference may be due to the relative phase of the dark photon field’s oscillations at these different positions. The physicists expect that both present Earth-based gravitational wave detectors such as LIGO, as well as future space-based gravitational wave detectors such as LISA (Laser Interferometer Space Antenna), will have the ability to search for dark photon dark matter. Using more than one detector would allow for cross-checking and better sensitivity. In the future, the scientists plan to work on further developing the new dark matter search method and determining exactly what kind of signal a gravitational wave detector would receive if a dark photon were nearby.”We plan to push this work well beyond a theoretical proposal,” Zhao said. “First, we plan to carry out the data analysis using a simplified signal model and a straightforward search algorithm. Then we will gradually refine our search method and include a detailed simulation of the signal and detector response.” Citation: Gravitational wave detectors to search for dark matter (2018, August 16) retrieved 18 August 2019 from https://phys.org/news/2018-08-gravitational-detectors-dark.htmllast_img read more

Evolution of magnetic field in the starforming complex G962019 revealed by ALMA

first_img High-mass stars play important role in the evolution of the universe. However, their physical mechanisms of formation are still not fully understood. For instance, one of the debated subjects is how magnetic fields of star-forming regions influence the formation and evolution of such massive stars.Observations of G9.62+0.19 (G9.62) could help resolve these uncertainties. This well-studied star-forming complex, located some 17,000 light years away, showcases several cores at different evolutionary stages. This region exhibits a fairly well established evolutionary sequence, and high-mass star formation is taking place there on a scale of several light years.A team of astronomers led by Daria Dall’Olio of Onsala Space Observatory in Sweden decided to observe G9.62 with ALMA, as its capabilities enable tracing magnetic fields even close to the inner parts of the star-forming cores. The observational campaign allowed them to investigate the magnetic field of G9.62 by analyzing its dust emission at 1 mm.”We aim to determine the magnetic field morphology and strength in the high-mass star-forming region G9.62+0.19 to investigate its relation to the evolutionary sequence of the cores. We make use of Atacama Large Millimeter Array observations in full polarization mode at 1 mm wavelength (Band 7) and we analyze the polarized dust emission,” the astronomers wrote in the paper.ALMA observations allowed the researchers to identify 23 protostellar cores and substructures in G9.62. Fundamental properties of these features were derived, such as their position, peak flux densities, integrated flux, position angles and spectral index. These data uncovered important insights about the region’s magnetic field.”In general, the magnetic field seemed to follow the direction of the filament, and it was perpendicular to the direction of the outflows emitted by some massive protostellar cores such has MM8a, MM7 and MM6. The cores that presented polarisation appeared to be less fragmented than the ones not showing polarised emission. At scales less than 0.1 pc, the magnetic field showed a neat and ordered pattern of polarisation vectors,” the paper reads.Furthermore, the researchers calculated that the strength of the magnetic field is at a level of about 11 mG. They also detected a linearly polarised molecular line, probably emitted thermally by methanol or carbon dioxide.All in all, the astronomers conclude that high magnetic field strength and the smooth polarised emission suggest that the magnetic field could play an important role in the star-forming processes in G9.62. They emphasized that the magnetic field could influence the fragmentation and the collapse process in this region, adding that the evolution of the cores could be magnetically regulated. More information: Daria Dall’Olio, et. al. ALMA reveals the magnetic field evolution in the high-mass star forming complex G9.62+0.19. arXiv:1905.00415 [astro-ph.SR]. arxiv.org/abs/1905.00415 Magnetic fields in massive star formation cores Explore further © 2019 Science X Network Using the Atacama Large Millimeter Array (ALMA), European astronomers have investigated the magnetic field of the high-mass star-forming region known as G9.62+0.19. Results of these observations, presented in a paper published May 1 on arXiv.org, provide insights into the evolution of this magnetic field, which could help astronomers better understand the role of magnetic fields in the formation of massive stars. Citation: Evolution of magnetic field in the star-forming complex G9.62+0.19 revealed by ALMA (2019, May 9) retrieved 18 August 2019 from https://phys.org/news/2019-05-evolution-magnetic-field-star-forming-complex.html Total intensity image of the star-forming region G9.62+0.19 at 1 mm wavelength. Credit: Dall’Olio et al., 2019. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

The Yale Happiness Class Distilled

first_imgIt’s a problem that may be particularly acute at a place like Yale, but the lessons of the class, called “Psychology and the Good Life,” are widely applicable—they address fundamental features of the human mind that make it difficult to appreciate things that seem like they’d be great. “Our minds are filled with a ton of little glitches that make it hard to enjoy the great things that we have,” as Laurie Santos, the psychology professor who teaches the course, puts it. Read the whole story: The Atlantic The most popular class in the history of Yale University was inspired by a paradox: Even when people, conventionally speaking, succeed—get into a top college, make lots of money, or accumulate prestige and accolades—they are often left feeling unsatisfied.last_img read more

Bengals best at a gallery near you

During the durga Puja, the Capital got to witness more creative streaks from the City of Joy. Calcutta-based gallery Akar Prakar got together with a bank and Round Table India to showcase a series of artworks by artists from Calcutta that started from 13 October. The exhibition consists of paintings by major contemporary artists from Bengal and targets young, upwardly mobile audiences, who look at art also as investment. Some of the artists whose works are being displayed are Beena Pradhan, Shipra Bhattacharya, Subrata Gangopadhyay, Suvaprasanna and Sanat Kar. There are a total of 15 artists. Also Read – ‘Playing Jojo was emotionally exhausting”The exhibition is mostly an introduction to art for clients of the bank’s Gurgaon branch. It has a mixed bag of artists — from young promising artists to masters,’ says Reena Lath, CEO, Akar Prakar. ‘The exhibition represents artists who would appeal to the new Indian art investor,’ adds Lath.The artworks include some of the very well known Bengal masters such as Paritosh sen, Sanat Kar, Suvaprasanna as well as some young artists such as Atin Basak, Mahajabin and Subir Dey. Lath maintains that the common theme for the exhibition is that all the artists are from Bengal. And no, none of the artworks were specially created for the exhibition. Rather, all of them have been taken from the gallery’s stocks. ‘There is no specific curation except for a broad theme,’ says Lath. So if you want more of Bengal, head to Gurgaon. read more

Shop for a cause

first_imgWondering what gift to pick up last minute for your near and dear ones? While you light those Diwali lamps, light up the lives of those not so privileged by heading to this Diwali bazaar. The Rotary delhi Midtown Diwali bazaar for a Cause has a host of gift items for all pockets. What’s more, the proceeds from the sale owing to the mall will go to the Rotary Club.   Shop for designer candles, diyas, pooja thalis, personalised gift packaging, ethnic apparel and accessories, chocolates, festive jewellery, home décor and furnishings and more. On sale are shimmering crystal curtains, bows and arrows, sterling silverware and silver-plated products like sculptural pieces in the form of Ganeshas, Shiva, Hanuman, Sai Baba, tea sets, trays, bowls, bar collection, salt and pepper dispenser sets, candle stands among others. So shop for a cause.DETAILAt: Select Citywalk, SaketOn Till: 13 NovemberTimings: 10 am to 11 pmlast_img read more

Flying without wings

first_imgEncapsulating the flavour of Lucknow, Patangbaaz is a play which explores the aspiration and dreams of three young boys from the city who want to do the unthinkable — fly kites throughout their lives. Lucknow exudes royalty with its Nawabi culture and language but there also exists a colloquial form of this language spoken by the youth in the city, as evident in the script.Actor Factor Theatre Company presents this hour-long play Patangbaaz which is written and directed by Shashwat Srivastava from Lucknow. Also Read – ‘Playing Jojo was emotionally exhausting’Explaining the concept of this play, Shashwat says: ‘Basically the play revolves around the life of three school boys, who are around 17 to 18 years old. I have tried to capture some glimpses of Lucknow through this play. The play is inspired from my personal experiences in this city where I have grown up. It focuses on the idea of how passionate people can be about what they want in their life and to what extent they can go to to achieve it. The play highlights the conviction of these three boys who want to fly kites against all odds.’ Also Read – Leslie doing new comedy special with NetflixAccording to Shashwat, the play celebrates the human spirit of freedom. These young boys constantly keep making efforts, while everyone starting from their family as well the tyrant school principal is against them flying kites, but they fight this battle and finally do what they want to.’Eventually they decide to give up everything possible to pursue their passion for flying kites,’ elucidates the playwright.The three school boys — Gopal, Mohan and Govind — dream of participating in Lucknow’s coveted Gomati Kite Flying tournament. Possessing a deep passion for kite flying, they ardently follow the festival and want to participate in it. They intensely discuss the contestants in the competition — Lakhna Dacoit and Kantha Pandey — the most dreaded kites in the contest. But to find their space in the sky, they must fight the barriers which society poses on them. The play highlights their fight with the social constraints which stop them from enjoying this sport. In this combative task, they even end up stealing kites from a local vendor and are then thrashed by their school’s principal. Finally, they decide to risk everything and live their dream.DETAILAt: Studio Safdar, Shadi Khampur, New Ranjit Nagar When: 25 NovemberTimings: 7.30 pmlast_img read more